The present invention introduces the method, equipment, and composition of fire prevention and suppression systems that utilize a low-oxygen (hypoxic) environment to:
Instantly extinguish an ongoing fire
Prevent a fire from getting started.
With its mode of action based on the controlled release of breathable fire-suppressive gases, this human-friendly system is completely non-toxic, fully automated, and entirely self-sustaining. Consequently, it is ideally suited to provide complete fire protection to houses, industrial complexes, transportation tunnels, vehicles, archives, computer rooms and other enclosed environments.
With the majority of fires (both industrial, and non-industrial) occurring at locations with a substantial amount of electronic equipment, this Fire Prevention and Suppression System (FirePASS(trademark)) has the added benefit of requiring absolutely no water, foam or other damaging agent. It can therefore be fully deployed without causing harm to the complex electrical equipment (and its stored data) that is destroyed by traditional fire suppression systems.
While this is extremely important to technology-intensive businesses such as banks, insurance companies, communication companies, manufacturers, medical providers, and military installations; it takes on even greater significance when one considers the direct relationship between the presence of electronic equipment and the increased risk of fire.
Current fire suppression systems employ either water, chemicals agents, gaseous agents (such as Halon 1301, carbon dioxide, and heptafluoropropane) or a combination thereof. Virtually all of them are ozone depleting, toxic and environmentally unfriendly. Moreover, these systems can only be deployed post-combustion. Even the recent advent of the Fire Master 200 (FM 200) suppression system (available from Kidde-Fenwal Inc. in the U.S.A.) is still chemically dependant and only retards the progression of fire by several minutes. Once this fire-retarding gas is exhausted, a sprinkler system ensues that results in the permanent destruction of electronic equipment and other valuables.
Exposure to FM-200 and other fire-suppression agents is of less concern than exposure to the products of their decomposition, which for the most part are highly toxic and life threatening. Consequently, there is no fire suppression/extinguishing composition currently available that is both safe and effective.
In terms of train, ship, or airplane fires, the inability to quickly evacuate passengers creates an especially hazardous situation. The majority of the passengers who died in France""s Mont Blanc tunnel fire suffocated within minutes. In this case the problem was further compounded by the presence of ventilations shafts. Originally designed to provide breathable air to trapped people, these shafts had the unfortunate side effect of dramatically accelerating the fire""s propagation. Especially devastating is the xe2x80x9cchimney effectxe2x80x9d that occurs in sloped tunnels. An example of this was the fire that broke out in Kaprun""s ski tunnel in Austrian Alps.
In addition, ventilation shafts (which are present in virtually all multilevel buildings and industrial facilities) significantly increase the risk of toxic inhalation. This problem is further compounded by the frequent presence of combustible materials that can dramatically accelerate a fire""s propagation.
While the proliferation of remote sensors has led to significant breakthroughs in early fire-detection, improvements in the prevention/suppression of fires has been incremental at best. For example, the most advanced suppression system to combat tunnel fires is offered by Domenico Piatti (PCT IT 00/00125) at robogat@tin.it. Based on the rapid deployment of an automated vehicle (ROBOGAT), the Robogat travels to the fire site through the affected tunnel. Upon arrival it releases a limited supply of water and foam to initiate fire suppression. If necessary, the Robogat can insert a probe into the tunnel""s internal water supply for continued fire-suppression. This system is severely limited for the following reasons:
The time that lapses between the outbreak of fire and the arrival of the Robogat is unacceptable.
The high temperatures that are characteristic of tunnel fires will cause deformation and destruction of the monorail, water and telecommunication lines.
The fire-resistance of the Robogat construction is highly suspected.
The use of water and foam in high-temperature tunnel fires is only partially effective and will lead to the development of highly toxic vapors that increase the mortality of entrapped people.
One of the main safety deficiencies in modern passenger airplanes that still remains unresolved is a lack of proper firefighting and fire preventing equipment.
In fact, it is not the flames associated with onboard fire that kills most flight crews and passengers, but rather the smoke saturated with toxins such as benzene, sulfur dioxide, formaldehyde, hydrogen chloride, ammonia and hydrogen cyanide. Although these and other chemicals are lethal, most victims die from carbon monoxide. This color- and odorless gas produced in abundance during fires, especially in enclosed compartments with insufficient ventilation, is extremely lethal even in small concentrations of less than one percent.
Toxic combustion products released in an enclosed compartment such as an aircraft cabin with no readily available escape means are of major concern in the air transport industry. This concern is of particular importance for passenger aircraft, because of constantly growing airplane capacity and increasing number of passengers that may be exposed.
The proliferation of toxic chemicals in modern advanced materials results in a cabin design completely made of plastics, fabrics, wiring and linings that can be extremely dangerous when they are heated sufficiently to produce gases. Survival in a toxic environment like this is limited to only a few minutes. Statistical analysis for the last decades shows that about 70-80 percent of fire fatalities result from toxic smoke inhalation.
A modern passenger aircraft is fully saturated with electric and electronic equipment, interconnected by many miles of wires and cables. Emergencies of various origins can lead to electric short-circuits with consequent inflammation of the insulating coat and surrounding flammable materials. This is followed by a massive production of toxic aerosols, which pose the main hazard, according to human fire fatality experience.
While the most important survival systems for aircraft, such as gas turbines and fuel tanks are sufficiently equipped with automatic fire-fighting systems, the passenger cabin and cockpit critically lack fire-preventive means. The use of standard fire-extinguishing substances, like Halon 2000 or the like, cannot resolve the problem, because of the high toxicity of the products of their pyrolysis. U.S. Pat. No. 4,726,426 (Miller) teaches such methods of fire extinguishing in an aircraft cabin as using ventilation ducts from the cargo fire extinguishing system, which would expose passengers to potentially lethal combinations of smoke, fire suppressants and highly toxic products of their pyrolysis.
In case of fire on board, pilots must complete an emergency checklist in order to localize the fire""s origin. A pilot""s emergency checklist is too long to let the crew control fires in the air. For the crew of the Swissair 111 that crashed near Nova Scotia in 1998, killing 299 people, it took 20 minutes after the first report of smoke untill the crash, while the standard checklist requires 30 minutes to complete.
It is supposed that oxygen masks would save passengers and flight crews from toxic inhalations. In reality airline pilots are instructed not to release the masks when the risk of an oxygen-fed fire would exacerbate the situation. Moreover, these masks are practically useless against combustions poisonous gases. Standard oxygen masks for flight crews and passengers have openings in them to mix the cabin air with the oxygen supply, thereby allowing a direct route for lethal gases to reach the lungs. Furthermore, the oxygen supply in a passenger aircraft provides less than 20% of the oxygen flow required for respiration and lasts for only a few minutes.
Alternatively, increasing the fresh air supply, as offered in ECHO Air system of Indoor Air Technologies Inc. in Canada, will only propagate a fire and accelerate its lethality. Their patent application provided on www.indoorair.ca teaches that an improved air ventilation system will allow the removal of contaminated air and supply fresh air into an aircraft cabin more efficiently. Claiming an improvement on fire safety, this method in practice improves the oxygenation of a fire source.
A recent study of the US Air Line Pilots Association (ALPA) suggests that in the year 1999, on average, one US airliner a day made an emergency landing because of a short circuit, which led to sparking, with resulting smoke and fire in the pressurized cabin. Faulty wiring is the leading culprit.
Some organizations have taken drastic action to deal with the problem. In 1987, the US Navy ordered the removal of the most vulnerable wiring from its planes, and in 1999 NASA grounded its entire fleet of space shuttles when a wiring fault led to a launch being aborted. Yet every day, millions of passengers are still carried by commercial aircraft that are equipped with old wiring that cannot be properly tested for faults. In the US, the Federal Aviation Administration (FAA) has been mounting a probe into the problems that may afflict aircraft that have been flying for more than 20 years. The Aging Aircraft Program has been running since 1988, prompted by an accident in which part of the roof peeled off an aging Boeing 737 in the sky over Hawaii. In 1996, TWA flight 800 came down off the coast of Long Island, killing all 230 people on board. Faulty wires inside a fuel tank were blamed as the most likely cause of the explosion. In the wake of that crash, checks on other airlines around the world led to the discovery of several other airplanes in which the insulation on aging wiring leading to sensors in fuel tanks had rubbed away through vibrations, or had been damaged during routine maintenance.
There are only 4 current methods of fire suppression in human-occupied facilities:
The use of water
The use of foam
The use of chemical flame inhibitors
The use of gaseous flame inhibitors
The present invention employs a radically different approach: the use of hypoxic breathable air for the prevention and suppression of fire. This hypoxic environment completely eliminates the ignition and combustion of all flammable materials. Moreover, it is completely safe for human breathing (clinical studies have proven that long term exposure to a hypoxic environment has significant health benefits). Hypoxic breathable air can be inexpensively produced in the necessary amount through the extraction of oxygen from ambient air.
In terms of fire prevention, a constantly maintained hypoxic environment can completely eliminate the possibility of fire while simultaneously providing an extremely healthy environment. In terms of suppression, this invention can instantly turn a normoxic environment into a hypoxic environment with absolutely no adverse effects to human life. This is extremely useful in the case of a flash fires or explosions.
Based on the exploitation of the fundamental differences between human physiology and the chemo-physical properties of combustion, this entirely new approach completely resolves the inherent contradiction between fire prevention and providing a safe breathable environment for human beings. Consequently, this invention is a radical advance in the management of fire and will make all current chemical systems obsolete
Hypoxic Fire Prevention and Suppression Systems will completely prevent the massive socioeconomic losses that result from the outbreak of fire.
The principal objects of this invention are as follows:
The provision of a breathable fire-extinguishing composition
A method for producing a fire preventive, hypoxic atmosphere inside human-occupied environments.
The provision of oxygen-depletion equipment that produces breathable, hypoxic air with fire-extinguishing properties. Such equipment employs the processes of molecular-sieve adsorption, membrane-separation and other oxygen extraction technologies.
The provision of breathable fire-extinguishing compositions for continuous or episodic use in human occupied environments.
The provision of the equipment and the method to instantly produce a fire-suppressive, oxygen-depleted atmosphere, where people can safely breath (without respiratory-support means). This can be accomplished by releasing a hypoxic fire suppression agent and creating fire-suppressive atmosphere having an oxygen content ranging from 10% to 17%.
The provision of a method for producing a fire-preventive atmosphere in hermetically sealed objects with controlled temperature and humidity levels. This can be accomplished by introducing inert ballast into artificial atmosphere and changing the initial settings of current life-support systems and reprogramming them.
The provision of hypoxic fire preventive/suppressive environments inside tunnels, vehicles, private homes (separate rooms or entire structures), public/industrial facilities and all other applications for non-hermetic human occupied environments.
The provision of a fire suppression system that instantly releases stored oxygen-depleted gas mixture from a high-pressure pneumatic system or an autonomous container.
The provision of a method and ability to localize a fire site through the use of drop curtains, doors or other means of physical separation; with the subsequent release of breathable, fire-suppressive gas mixtures.
The provision of an aircraft fire suppression system utilizing a hypoxic fire suppression agent for producing a breathable atmosphere onboard having fire-extinguishing properties.
The provision of an aircraft fire suppression system having a flexible inflatable container for storage of the hypoxic fire suppression agent.